Crossover protection apparatus



Patented Feb. 19, 1952 CROSSOVER PROTECTION APPARATUS Thomas W. Tizzard, Jr., Downers Grove, 111., as-

signor to Westinghouse Air Brake Company, a corporation of Pennsylvania Application February 26, 1947, Serial No. 730,958

12 Claims. 1

My invention relates to crossover protection apparatus, and particularly to apparatus for providing crossover protection for trains movin along railway tracks which are connected with each other by a crossover track through handoperated track switches.

A requisite for crossover protection apparatus is that it must be so arranged that a car or locomotive while occupying a crossover such, for example, as one connecting two main tracks,

while the switches are in the normal position for train movements along the main tracks, will cause a signal for each main track to indicate stop if the car or locomotive is within fouling distance of that main track.

One feature of my invention is the provision of means for energizing one crossover track relay from each of the track circuits for the main track sections which include the switches of the crossover track.

Another feature of my invention is the provision of asymmetric means for each end of the crossover track for continuing energization of the crossover track relay from either of these main track circuits while the other main track circuit is deenergized.

I shall describe two forms of apparatus embodying my invention, and shall then point out the novel features thereof in claims.

In the accompanying drawings, Fig. 1 is a diagrammatic view showing one form of apparatus embodying my invention, in which one track relay for a crossover track is energized from each of the adjacent main track circuits through a corresponding half-wave rectifier, and in which the crossover track relay, upon becoming deenergized, such, for example, as by a train on the crossover track, opens both of these main track circuits and places a shunt across the relayend of each of them; and Fig. 2 is a diagrammatic view showing a modification of the apparatus of Fig. 1, in which the crossover track relay, upon becoming deenergized, opens line circuits for controlling signals for the main tracks instead of controlling the main track circuits.

Similar reference characters refer to similar parts in each of the views.

' Referring first to Fig. 1, a stretch of railway is shown comprising two main tracks designated by the reference characters IT and 2T, interconnected by a crossover track designated by the reference character 3T, through hand-operated switches IW and 2W. A pair of insulated joints 4 and 5 is provided in each end of track 3T. Joint l of each of these pairs is located in the frog side of track 3T between the rails of the adjacent main track, and joint 5 of each pair is located in the other side of the crossover track adjacent the heel of the switch at its end of track 3T.

Track IT is divided by insulated joints 6 to form a section adjacent crossover track 3T which includes switch IW. Track 2T is divided by insulated joints Ii to form a section adjacent crossover track 3T which includes switch 2W.

A track circuit is provided for each of these sections of main track, including a suitable source of current, shown as a battery I, connected through a usual impedance 8 across the rails adjacent one end of the section, and a track relay, designated by a reference character which is the same as the reference character for its track except including the letter R instead of the letter T, connected across the rails adjacent the opposite end of the section.

A track relay, designated by the reference character 3R, is connected across the rails of crossover track 3T at some point between the pairs of insulated joints 4 and 5.

An asymmetric unit, designated by the reference character IM, which may be of the wellknown copper oxide half-wave rectifier type, is connected between rail Ia of track IT and rail 3b of track 3T which is insulated from track IT by one of the insulated joints 5. A second asymmetric unit, designated by the reference character 2M, is similarly connected between rail 2b of track 2T and rail 3a of track 3T which is insulated from track 2T by the other insulated joint 5.

Contact 9, operated in conjunction with switch IW, is arranged to be normally open when switch IW is in its normal position, as shown, for traflic movements along main track IT, but to become closed in a shunt path across rails Ia and lb of track IT when switch IW is in its reverse position for a traflfc movement over crossover track 3T. A similar contact 9 is similarly operated in conjunction with switch 2W for closing a shunt path across rails 2a and 2b of track 2T when switch 2W is in its reverse position for a traflic movement over the crossover track 3T.

Rail Ia of track IT and rail 2a of track 2T are divided by insulated joints I0 adjacent relay 3R. A path around each of the joints I0 is closed by a front contact of relay 3R, and a shunt path across the rails of each of the tracks IT and 2T on the track relay side of its insulated joint I0 is closed by a back contact of relay 3R.

A signal IS for track IT is controlled by a front Feb. 19, 1952 w, TlZZARD, JR 2,586,491

CROSSOVER PROTECTION APPARATUS Filed Feb. 26, 1947 1 N VEN TOR.

H15 ATTORNEY.

Thong Tz'zzar'd Jr.

BY g

arsenal 7 including a track relay and a source of current and connected through asymmetric means to said crossover track section to energize said crossover track relay and not to energize the track relay for the other main track circuit.

8. crossover protection apparatus for a stretch of railway in which two .main tracks are interconnected by a crossover track atone endof which there is a first switch for connection with one of said main tracks and rat the other end of which there is a second switch for connection with the other main track, and in which a section of each of said main tracks is set off includin the switch at its end of said crossover track, the combination comprising, a section of said crossover track one side of which is insulated from one of said :main track sections and the other side of which is insulated from the other of said main :track sections, a track relay connected across the rails-of said crossover track section, and a track circuit for each of said main track sections each including a track relay and a source of current and connected through asymmetricmeans to said crossover track section to energize said crossover track relay while the other main track circuit is shunted.

9.. In crossover protection apparatus for a stretch of railway in which two main tracks are interconnected by a crossover track at oneend of which there is a first switch for connection with one of said main tracks and at the other end of which there ,is a second switch for connection with the other main track, and'in which a section of each of said main tracks set-off including the switch "at its end of said crossover track, the com-' binaticn comprising, a track relay connected across the rails of said crossover track, a track circuit for each of said main track sections each including a source of current and a track relay and each arranged to energize said-crossover track relay, and means controlled by said crossover track'relay when deenergized for deenergizingsaid -main track circuit relays.

10. In crossover protection apparatus for a track circuit for each of said main track sections track sections on the track relay side :of the said insulated joint for the same section each including a hack contact of said crossover track relay.

11. In crossover protection apparatus Ior a stretch of railway in which two main tracks are interconnected by a crossover track at one end of which there .is a first switch for connection with one of said main tracks and at the other end of which there a second switchior connection with the other track, and in which aisection iOf each of said main tracks isse't ofi including the switch at its end .of said crossover track, the com- ;bination comprising, a section of said crossover track one side of which is insulated from one'oi said main track sections and the other side of which is insulated from the other of said ,main track sections, a track relay connected across the rails of said crossover track section, ,a tnacktcircuit for each of said main track sections each arranged to energize said crossover track relay, asymmetric means connected to block the flow of current .from either of said main track sections to the other and traflic governing means for-each of said main tracks controlled by said crossover track relay.

.12. In crossover protection apparatus for a stretch of railway in which two main tracks are interconnected by a crossover track'at one end of which there is a first switch (for connection with one of said main tracks and at the otherend of which there is asecond switch for connection with the other main track, in which a section of each of said main tracks including the switch at its end of said crossover track .is provided with, a track circuit including .a source of unidirectional current, and in which there is a pair of insulated joints in each end of said crossover track one joint of each of said pairs located in the frog side of said crossover track between the rails of the adjacent .main track and the other joint of each of said pairs located in the other side of said crossover track adjacent the heel of the corresponding switch, the combination comprising, a track relay connected across the rails of said crossover track, and an asymmetric unit for each end .of said crossover track each of said asym- '-metric units included in a circuit path one end of which is connected to the .rail of said crossover track which is insulated .from the rail of the frog side or the adjacent main track and theopposfite end of said circuit path connected to the opposite vvrail of the adjacent .main track with the lowresistance direction of one of said asymmetric units from the adjacent main track to said crossover track and 'thelow resistance direction of the other asymmetric unit from said crossover track to the other main 'track while said source of "unidirec- 'tional current for each of said main tracks connected to send current through the corresp'onding asymmetric unit.

'I HONIAS T-IZZARD, 51R.

No references cited.

Although I have herein shown and described only two forms of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In crossover protection apparatus for a stretch of railway in which two main tracks are interconnected by a crossover track at one end of which there is a first switch for connection with one of said main tracks and at the other end of which there is a second switch for connection with the other main track, and in which a section of each of said main tracks is set ofi including the switch at its end of said crossover track, the combination comprising, a track circuit for each of said main track sections each including the rails of its section and a source of unidirectional current, a section of said crossover track one side of which is insulated from one of said main track sections and the other side of which is insulated from the other of said main track sections, a track relay connected across the rails of said crossover track section, and means including two asymmetric units each connected between one side of said crossover track section and the main track section from which it is insulated for energizing said track section relay from said track circuits.

2. In crossover protection apparatus for a stretch of railway in which two main tracks are interconnected by a crossover track at one end of which there is a first switch for connection with one of said main tracks and at the other end of which there is a second switch for connection with the other main track, and in which a section of each of said main tracks is set ofi including 'the switch at its end of said crossover track, the

combination comprising, a track circuit for each i of said main track sections each including a source of unidirectional current connected across the rails of its section in given polarity relation to the track circuit for the other main track section, a track relay connected across the rails of said crossover track, a section of said crossover track one side of which is insulated from one of said main track sections and the other side of which is insulated from the other of said main track sections, andmeans including asymmetric units connected between said crossover track section and said main track sections for energizing said track relay from said track circuits.

3. In crossover protection apparatus for a stretch of railway in which two main tracks are interconnected by a crossover track at one end of which there is a first switch for connection with one of said main tracks and at the other end of which there is a second switch for connection with the other main track, and in which a section of each of said main tracks is set ofi including the switch at its end of said crossover track, the combination comprising, a section of said crossover track one rail of which is insulated from one of said main tracks and the other rail of which is insulated from the other main track, a source of unidirectional current for each of said main track sections connected across the rails of its section, two asymmetric units one connected between said crossovertrack section and one of said main track sections and the other connected between said crossover track section and the other main track section, and a track relay connected across the rails of said crossover track energized by current from said main track sections passing through said asymmetric units.

4. In crossover protection apparatus for a stretch of railway in which two main tracks are interconnected by a crossover track, the combination comprising, a source of unidirectional current for each of said main tracks each of said sources connected across the rails of its main track, a section of said crossover track one rail of which is insulated from one of said main tracks and the other rail of which is insulated from the othermain track, two asymmetric units one of which is connected between one of said main tracks and the rail of said crossover track section which is insulated from said one main track and the other asymmetric unit connected between the other main track and the rail of said crossover track which is insulated from said other main track, and a track relay connected across the rails of said crossover track section energized by current from said main track sections passing through said asymmetric units.

5. In crossover protection apparatus for a stretch of railway in which two main tracks are interconnected by a crossover track at one end of which there is a first switch for connection with one of said main tracks and at the other end of which there is a second switch for connection with the other main track, and in which a section of each of said main tracks is set oif including the switch at its end of said crossover track, the combination comprising, a section of said crossover track one side of which is insulated from one of said main track sections and the other side of which is insulated from the other of said main track sections, a track relay connected across the rails of said crossover track section, and a track circuit for each of said main track sections each connected with said crossover track section to energize said crossover track relay.

6. In crossover protection apparatus for a stretch of railway in which two main tracks are interconnected by a crossover track at one end of which there is a first switch for connection with one of said main tracks and at the other end of which there is a second switch for connection with the other main track, and in which a section of each of said main tracks is set 01f including the switch at its end of said crossover track, the combination comprising, a track relay connected across the rails of said crossover track, a track circuit for each of said main track sections each including a track relay and each arranged to energize said crossover track relay, and

. asymmetric units connected between said main track sections and said crossover track for preventing energization of the track relay for either of said main track circuits by the other main track circuit.

7. In crossover protection apparatus for a stretch of railway in which two main tracks are interconnected by a crossover track at one end of which there is a first switch for connection with one of said main tracks and at the other end of which there is a second switch for connection with the other main track, and in which a section of each of said main tracks is set off including the switch at its end of said crossover track, the combination comprising, a section of said crossover track one side of which is insulated from one of said main track sections and the other side of which is insulated from the other of said main track sections, a track relay connected across the rails of said crossover track section, and a track circuit for each of said main track sections each 

